Sisäilman laatuun vaikuttavat tekijät

Tiivistelmä. Tämän kandidaatintyön tavoitteena on esitellä sisäilman laatuun vaikuttavia tekijöitä. Näihin tavoitteisiin päästiin tutustumalla aihealueen keskeisiin tutkimuksiin. Työn tavoitteena oli luoda selkeä ja helposti ymmärrettävä kokonaisuus erilaisista sisäilmatekijöistä. Työ on rajattu sisäilman laatuun vaikuttaviin tekijöihin ja ne on pyritty avaamaan mahdollisimman tarkasti. Sisäilman laatuun vaikuttavat todella monet eri tekijät yhdessä ja erikseen. Sisäilmaongelmia epäiltäessä onkin haastavaa yksilöidä sen lähteitä. Selkeitä ohjeita ja raja-arvoja ei ole vieläkään saatavilla ongelmien osoittamiseksi. Hyvän sisäilman takaamiseksi on tärkeää huolehtia talotekniikan ja rakenteiden kunnosta sekä siisteydestä. Ennakointi onkin avainasemassa sisäilmaongelmien ja niistä aiheutuvien terveyshaittojen ehkäisemisessä.Factors that influence indoor air quality. Abstract. The aim of this bachelor’s thesis is to get acquainted with the factors influencing indoor air quality. These objectives were achieved by reviewing key studies in the field. The aim of the thesis was to create a clear and easily understandable set of different indoor air factors. The work is limited to the factors affecting indoor air quality, and efforts have been made to open these as closely as possible. There are many different factors that influence the quality of indoor air together and separately. It is therefore challenging to identify the sources of indoor air quality problems. Clear guidelines and thresholds are still not available to address the problems. In order to ensure good indoor air, it is important to maintain the integrity and cleanliness of the building technology and structures. Foresight is therefore a key element in preventing indoor air problems and the resulting health damage

Picosecond timing of Microwave Cherenkov Impulses from High-Energy Particle Showers Using Dielectric-loaded Waveguides

We report on the first measurements of coherent microwave impulses from high-energy particle-induced electromagnetic showers generated via the Askaryan effect in a dielectric-loaded waveguide. Bunches of 12.16 GeV electrons with total bunch energy of $\sim 10^3-10^4$ GeV were pre-showered in tungsten, and then measured with WR-51 rectangular (12.6 mm by 6.3 mm) waveguide elements loaded with solid alumina ($Al_2 O_3$) bars. In the 5-8 GHz $TE_{10}$ single-mode band determined by the presence of the dielectric in the waveguide, we observed band-limited microwave impulses with amplitude proportional to bunch energy. Signals in different waveguide elements measuring the same shower were used to estimate relative time differences with 2.3 picosecond precision. These measurements establish a basis for using arrays of alumina-loaded waveguide elements, with exceptional radiation hardness, as very high precision timing planes for high-energy physics detectors.Comment: 16 pages, 15 figure

Puhalluseristettyjen yläpohjien lämpötekniset ominaisuudet ja niiden mitoitus

Tiivistelmä. Työn tarkoituksena on tutustua puhalluseristettyjen yläpohjien lämpöteknisiin ominaisuuksiin. Rakennushankkeeseen pakolliseksi tuleva elinkaarimallin mukainen hiilijalan- ja hiilikädenjäljen laskenta suoritetaan 140 neliömetrin omakotitalon ja 3000 neliömetrin maatalousrakennuksen lämmöneristeille. Niiden avulla lämmöneristeen valinnasta johtuvia ympäristövaikutuksia pystytään vertailla. Työssä lasketaan erilaisilla hyväksyttävillä menetelmillä lämmönläpäisykerroin tyypilliselle yläpohjarakenteelle ja tuloksia verrataan aikaisempien tutkimusten pohjalta laskettuihin todellisia olosuhteita vastaaviin arvoihin. U-arvot lasketaan EN-standardien, RIL:n suunnitteluohjeen ja COMBI-hankkeen tuloksista johdettujen arvojen mukaisesti. COMBI-hankkeen tulokset kuvaavat todellisia yläpohjan olosuhteita. Selluvillan ympäristövaikutukset ovat huomattavasti pienemmät kuin mineraalivilloilla. Tämä näkyy pienenä hiilijalanjälkenä. Selluvilla on myös ainut puhallettava lämmöneriste, joka sitoo hiiltä ja jolla on hiilikädenjälki. Tulokset osoittavat, että EN-standardien mukainen mitoitus antaa huomattavasti todellista tilannetta paremmat U-arvot kaikille puhallettaville lämmöneristeille. Sisäinen konvektio alkaa monien tutkimusten mukaan jo pienillä lämpötilaeroilla ja kerrospaksuuksilla. RIL:n suunnitteluohjeen mukainen mitoitus on pienemmän ilmanläpäisevyyden omaavalla selluvillalla lähes todellisia tilanteita vastaava. Suuremman ilmanläpäisevyyden omaavan lasivillan tapauksessa ohje antaa liian pieniä lämmönläpäisykertoimia. Lasivillalla myös eristekerroksen pintaan vaikuttava ilmavirtaus lisää huomattavasti lämpövirtaa eristeen läpi. U-arvon laskenta on jatkossa suositeltavaa tehdä RIL:n suunnitteluohjeen mukaisesti. Ohjeessa otetaan ilmanläpäisevyys huomioon lisäterminä. Tulosten mukaan lisätermin kerroin on suurilla ilmanläpäisevyyksillä riittämätön. Hyväksyttävässä lämmönläpäisykertoimen laskennassa tulisi aina ottaa ilmanläpäisevyys huomioon erityisesti Suomen kaltaisissa kylmissä ilmasto-oloissa.Thermal properties and design of loose-fill insulated roofs. Abstract. The purpose of the work is to find out the thermal properties of the loose-fill insulated roofs. The calculation of the carbon footprint and carbon handprint, which will be mandatory for the construction project, will be carried out in 140 m² for the heat insulation of the detached house and 3000 m² for the agricultural building. They make it possible to compare the environmental impacts of heat insulation selection. The work is calculated using different acceptable methods to calculate the heat permeability factor for the typical superstructure and the results are compared to the actual values calculated from previous studies. U-values shall be calculated in accordance with ENstandards, RIL design guidelines and values derived from the results of the COMBIproject. The results of the COMBI-project reflect the real conditions of the loose-fill insulated roofs. The environmental impact of wood fibre insulation is significantly lower than mineral wools. This can be seen as a small carbon footprint. Wood fibre insulation is also the only loose-fill insulation that binds carbon and has a carbon handprint. The results show that design according to EN-standard gives significantly better U-values than the actual situation for all loose-fill insulations. According to many studies, internal convection begins with small temperature differences and layer thicknesses. The design according to the RIL design guidelines is almost equivalent to the actual situation for loose-fill insulations with a lower air transmittance. Materials with a greater air transmittance like glass wool, the instructions provide too small heat transmittance factors. In glass wool, the air flow affecting the surface of the insulation layer also significantly increases the heat flow through the insulation. In the future, it is recommended to calculate the U-value according to RIL’s design instructions. In the instructions, air permeability is taken into account as an additional term. According to the results, the coefficient of the additional term is insufficient for greater air permeability. Air permeability should always be taken into account in an acceptable heat transfer coefficient calculation, especially in cold climates like Finland

Prefrontal microcircuit underlies contextual learning after hippocampal loss

Specific brain circuits have been classically linked to dedicated functions. However, compensation following brain damage suggests that these circuits are capable of dynamic adaptation. Such compensation is exemplified by Pavlovian fear conditioning following damage to the dorsal hippocampus (DH). Although the DH normally underlies contextual fear and fear renewal after extinction, both can be learned in the absence of the DH, although the mechanisms and nature of this compensation are currently unknown. Here, we report that recruitment of alternate structures, specifically the infralimbic and prelimbic prefrontal cortices, is required for compensation following damage to the hippocampus. Disconnection of these cortices in DH-compromised animals and immediate early gene induction profiles for amygdala-projecting prefrontal cells revealed that communication and dynamic rebalancing within this prefrontal microcircuit is critical. Additionally, the infralimbic cortex normally plays a role in limiting generalization of contextual fear. These discoveries reveal that plasticity through recruitment of alternate circuits allows the brain to compensate following damage, offering promise for targeted treatment of memory disorders

Accelerator measurements of magnetically-induced radio emission from particle cascades with applications to cosmic-ray air showers

For fifty years, cosmic-ray air showers have been detected by their radio emission. We present the first laboratory measurements that validate electrodynamics simulations used in air shower modeling. An experiment at SLAC provides a beam test of radio-frequency (RF) radiation from charged particle cascades in the presence of a magnetic field, a model system of a cosmic-ray air shower. This experiment provides a suite of controlled laboratory measurements to compare to particle-level simulations of RF emission, which are relied upon in ultra-high-energy cosmic-ray air shower detection. We compare simulations to data for intensity, linearity with magnetic field, angular distribution, polarization, and spectral content. In particular, we confirm modern predictions that the magnetically induced emission in a dielectric forms a cone that peaks at the Cherenkov angle and show that the simulations reproduce the data within systematic uncertainties.Comment: 5 pages, 7 figure

Observations of the Askaryan Effect in Ice

We report on the first observations of the Askaryan effect in ice: coherent impulsive radio Cherenkov radiation from the charge asymmetry in an electromagnetic (EM) shower. Such radiation has been observed in silica sand and rock salt, but this is the first direct observation from an EM shower in ice. These measurements are important since the majority of experiments to date that rely on the effect for ultra-high energy neutrino detection are being performed using ice as the target medium. As part of the complete validation process for the Antarctic Impulsive Transient Antenna (ANITA) experiment, we performed an experiment at the Stanford Linear Accelerator Center (SLAC) in June 2006 using a 7.5 metric ton ice target, yielding results fully consistent with theoretical expectations

Observations of Microwave Continuum Emission from Air Shower Plasmas

We investigate a possible new technique for microwave measurements of ultra-high energy cosmic ray (UHECR) extensive air showers which relies on detection of expected continuum radiation in the microwave range, caused by free-electron collisions with neutrals in the tenuous plasma left after the passage of the shower. We performed an initial experiment at the AWA (Argonne Wakefield Accelerator) laboratory in 2003 and measured broadband microwave emission from air ionized via high energy electrons and photons. A follow-up experiment at SLAC (Stanford Linear Accelerator Center) in summer of 2004 confirmed the major features of the previous AWA observations with better precision and made additional measurements relevant to the calorimetric capabilities of the method. Prompted by these results we built a prototype detector using satellite television technology, and have made measurements indicating possible detection of cosmic ray extensive air showers. The method, if confirmed by experiments now in progress, could provide a high-duty cycle complement to current nitrogen fluorescence observations of UHECR, which are limited to dark, clear nights. By contrast, decimeter microwave observations can be made both night and day, in clear or cloudy weather, or even in the presence of moderate precipitation.Comment: 15 pages, 13 figure